The present invention relates to a process for the preparation of poly-piperazinamide anisotropic shaped articles suitable for ultrafiltration and for reverse osmosis.
With the term "poly-piperazinamides", as used in the present description and relative claims, are intended all polycondensed products of piperazine or piperazine alkyl-substituted, optionally in admixture with other diamines, with anhydrides or dichlorides of saturated or unsaturated aliphatic, aromatic or heterocyclic di-carboxylic acids, such as, for instance, fumaric acid, mesaconic acid, adipic acid, phthalic acid, isophthalic acid, ring substituted phthalic acids or heterocyclic acids derived from furazane, thio-furazane, pyridine, thio-phene and the likes, either by themselves or in admixture with each other. These polypiperazinamides are disclosed in U.S. Pat. Nos. 3,687,842; 3,743,596; 3,743,597; 3,696,031; 4,129,559 and 4,123,424.
The term "anisotropic shaped article" comprises flat membranes and hollow fibers having a dense and homogeneous layer which makes possible a high repelling solute capacity, and an underlying porous layer acting as a support.